发表机构
Friedrich-Alexander-Universität Erlangen-Nürnberg; Physikalisch-Technische Bundesanstalt; Ludwig-Maximilians-Universität（埃尔朗根-纽伦堡弗里德里希·亚历山大大学; 德国联邦物理技术研究院; 慕尼黑路德维希-马克西米利安大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文在纳米金尖端阵列强场光发射中首次实验观测到通道闭合现象，并利用其作为精密量规原位测量局部增强光学近场强度，为光波光电子器件提供仅需电流测量的诊断工具。
AI 中文摘要
超快光发射是发展拍赫兹电子学的一条有前景的途径。对于此类器件，识别精确的发射机制并量化发射位点处的局部场强至关重要。虽然这些信息可以从电子能量谱或发射率随峰值强度的标度关系中提取，但此类测量在技术上并非总是可行，且对结果的清晰解释可能具有挑战性。在此，我们展示了通道闭合作为局部增强光学近场强度的精密量规。通道闭合源于场诱导的真空能级上移，这导致发射产额随强度增加而小幅下降。我们报告了在纳米尖锐金尖端阵列的光发射速率中首次实验观察到此类通道闭合。我们的数据与模拟产额高度吻合，从而能够原位精确测量尖端阵列处的局部场增强光学近场。我们预期该方法可作为光波光电子器件表征的多功能诊断工具，因为它仅需测量电流即可。
英文摘要
Ultrafast photoemission is a promising avenue for the development of petahertz electronics. For such devices, identifying the precise emission mechanism and quantifying the local field strength at the emission site are of utmost interest. While this information can be extracted from electron energy spectra or the scaling of the emission rate with peak intensity, such measurements are not always technically feasible and a clear interpretation of the results can be challenging. Here, we demonstrate channel closing as a precision gauge for the local enhanced optical nearfield strength. Channel closings originate from a field-induced upshift of the vacuum level, which leads to a small decrease of the emission yield with increasing intensity. We report the first experimental observation of such channel closings in the photoemission rate from an array of nanometer-sharp gold tips. Our data are well matched by simulated yields, enabling us to precisely measure the local, field-enhanced optical nearfield at the tip array in situ. We expect this method to be a versatile diagnostic tool for the characterization of lightwave optoelectronic devices, as it suffices to measure currents only.
Comments6 pages, 4 figures
